where's the power plant?

[wingaurd]

where's the power plant in silver/gold?

[Suicune Trainer]

It's on the exact same place it is in R/B/Y.

Go to Cerulean, you need to carry Pokémons with Cut and Surf.
Go to the West side of Cerulean and cut the three blocking the rute, kepp walking untill you find a grassland, next to a body of water, very close to the Rock Tunnel and a Pokécenter. Go to the water and Surf west and then so south untill you find land again. A building must be there.

Now, on R/B/Y the Power Plant contains many electric Pokémon, even Zapdos, here, in G/S you get a TM that contains Zap Cannon, and they give it to you after you fix the Magnet Train.